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### Re: Chooch's 3D printable laser cutter

Posted:

**Mon Jul 25, 2011 10:45 pm**
by **trwalters001**

This is a great idea!

However, if you use 2 line-generator lasers, 90 degrees to each other, they'll cross at the focal point whatever distance you're focusing at.

Tim

### Re: Chooch's 3D printable laser cutter

Posted:

**Mon Jul 25, 2011 11:13 pm**
by **bdring**

The idea is to use dots. This way it will also allow you to set the focal length too. Cross hairs only work in 2 dimensions.

There is only one point in 3D space where the dots overlap.

### Re: Chooch's 3D printable laser cutter

Posted:

**Tue Jul 26, 2011 9:29 pm**
by **Hassi**

hi, i tryed to combine each idea of you.

ended with this:

its only shematic

### Re: Chooch's 3D printable laser cutter

Posted:

**Tue Jul 26, 2011 10:06 pm**
by **bdring**

Two lines and a dot? I guess that would work.

One of the features of the two dots method comes into play if the beams are at a 45 degree angle. The distance between the dots is equal to the distance away from the focal point. Sometimes I like to focus below the surface at the middle. This could help you quickly estimate the middle.

The two lines and a dot might have a similar affect, but you do not need to converge the dots first. The crossed lines will give you the XY and the dot gives the distance to the Z.

### Re: Chooch's 3D printable laser cutter

Posted:

**Wed Jul 27, 2011 2:30 pm**
by **trwalters001**

Bart wrote:The distance between the dots is equal to the distance away from the focal point.

Never thought of that...

*THIS* is why you get paid the big bucks!

### Re: Chooch's 3D printable laser cutter

Posted:

**Mon Sep 19, 2011 12:12 pm**
by **iGull**

Hi

bdring wrote:The distance between the dots is equal to the distance away from the focal point.

Hadn't read this log before - this is the system that the 'Dambusters' used in WWII

Checkout ...

http://en.wikipedia.org/wiki/File:Dambstrajj.gifI guess a pair of lasers would have been slightly more accurate !

Cheers

Neil